Taurine has been reported to have both antirrhythmic and positive inotropic effects on the heart. It has been proposed that taurine may exert these effects by altering calcium and potassium movement in the myocardial cell. Experiments to test this hypothesis with perfused rat heart and in vitro models are being proposed. Evidence will also be sought to define the physiological significance of isethionic acid in the heart. These will involve both examination of its metabolism and its physiological effects on the isolated heart.